Electroplating barrel



Jan. 6, 1953 s. DUBPERNELL ETAL 2,624,728

ELECTROPLATING BARREL 5 Sheets-Sheet 1 Filed July 14, 1949 INVENTORSGEOEQE DUBPERNELL ST PH NM.MA/2T/N AT TORNEY Jan. 6, 1953 e. DUBPERNELLEI'AL' 2,624,723

ELECTROPLATING BARREL Filed July 14, 1949 S Sheets-Sheet 2 INVENTORSZGEORGE DUBPERNELL S EPEN M. MARTIN BY: v

ATTORNEY Jan. 6, 1953 G. DUBPERNELL ETAL 2,624,723

ELECTROPLATING BARREL Filed July 14, 1949 s Sheets-Sheet :5

Fig. 8

INVENTORS. GEORGE DUBPERNELL 3 TE H M. MART/N ATTORNEY Jan. 6, 1953 G.DUBPERNELL ET AL 2,

ELECTROPLATING BARREL Filed July 14, 1949 5 Sheets-Sheet 4 INVENTORSLGEORGE DUBPERNELL jHEN M. MART/N BY'. I

IA TTOR 35% Jan. 6, 1953 G. DUBPERNELL EI'AL 2,624

ELECTROPLATING BARREL Filed July 14, 1949 5 Sheets-Sheet 5 AUTOMATIC 140HOPPER FEED INVENTORs'. GEORGE DUBPERNELL jg: E MMAET/N BYI {{TORNEY 3Patented Jan. 6, 1953 ELECTROPLATIN G BARREL George Dubpernell,Watertown,

Conn, and

Stephen M. Martin, Glen Ridge, N. J assignors to United Chromium,Incorporated, New York, N. Y., a. corporation of Delaware ApplicationJuly 14, 1949, Serial No. 104,757

1 Claim. 1

This invention relates to electroplating barrels, particularly for usein electrodepositing metals which are difficult to plate.

Chromium has been a metal which has presented difliculties toelectroplating in barrels. Good electrical contacts, anode design andspacing, and speed of rotation of the barrel are important. Hygroscopicand corrosive constituents of the plating solution make it important toavoid fouling and corrosion of bearings and electrical connections,especially sliding connections. It is also important to remove the anodefrom the plating solution when current is not flowing. The feeding andremoval of articles from the barrel without removal of the barrelcylinder from the plating solution has been troublesome.

The present invention provides an electroplating barrel Well adapted forelectrodepositing difficult metals such as chromium, which is sturdy andmechanically simple, and in which good electrical and bearingsperformances are obtained. The anode support construction provides forready disassembly of the anode from the barrel, ready substitution ofanodes, ready adjustment of anode to cathode spacing and ready removalof the anode from the solution without disassembly. The invention alsoprovides novel and useful means for, and constructional adaptation to,feeding and removal of articles to and from the barrel cylinder.

Three embodiments of the invention are illustrated in the accompanyingdrawings, wherein Figure 1 is a top plan view of one embodiment;

Figure 2 is a. vertical sectional view of the construction shown inFigure 1;

Figure 2a is a detail sectional view of one corner of the barrelcylinder, showing the insulation;

Figures 3 and 4 are end elevations, partly in section on line X-X, Fig.1, Fig. 3 showing the an ode in the solution and Fig. 4 showing theanode rotated on its support out of the solution;

Figure 5 is a transverse section through the barrel cylinder showingscoops for removing plated articles from the barrel cylinder;

Figure 6 is a view similar to Fig. 5 and showing the scoops fordepositing and removing articles from the barrel cylinder;

Figure '7 is a sectional detail for the barrel cylinder;

Figure 8 is a view mainly in vertical section illustrating a secondembodiment and incorporating means for continuously feeding and removingarticles from the barrel cylinder;

Figure 9 is a top plan view of the construction illustrated in Fig. 8;

view of a bearing Figure 10 is an end elevation of the barrel cylinder,partly in transverse section, at the delivery end of the cylinder;

Figure 11 is a view in end elevation of the barrel cylinder at thefeeding end thereof;

Figure 12 is a detail View showing a means for adjusting the height ofthe anode supports 15 and H and thereby adjusting the spacing betweenthe anode and the work resting on the inside of the barrel cylinder;

Figure 13 is a partial vertical sectional view of a third embodiment ofthe invention;

Figure 14 is a plan view of the feed chute seen in Figure 13.

Referring to said drawings, numeral [0 designates a, suitable tank forcontaining an electroplating solution and numeral l2 designates acylindrical barrel rotatable on a horizontal axis, and circumferentiallycontinuous, as shown. Numeral l4 designates a means for controlling thetemperature of the electroplating solution in the tank, such as commonlyemployed, and as here shown, consists of a coil of pipe immersed in thesolution and having an inlet 15 and an outlet I6 for a cooling orheating medium such as water or steam. Means for stirring the solutionmay be provided, as indicated by numeral 20. Spray and fumes above thelevel of the solution in the tank may be drawn away, as usual, by anysuitable form of means, as the fan 22 driven by motor 23. The level ofthe solution in the tank may be controlled by an opening 25 in one ofthe walls of the tank, and a down-spout 26 which leads to a suitableoverflow receptacle.

The barrel cylinder i2 is made of a suitable electrical conductingmaterial as steel and is open at both ends to the solution in the tank,as indicated at 28, 29. The electroplating solution may circulatethrough the barrel, through the end openings. Flanges 30, 3| areprovided at the two ends of the barrel cylinder to prevent work beingelectroplated falling out. Articles being electroplated in the barrelcylinder rest in electrical contact with the inner cylindrical metalsurface of the barrel cylinder. That is, the inner cylindrical surfaceis base metal. The flanges 3i), 3! are faced with or formed ofinsulating material as indicated at 33, 34 to prevent these parts fromdiverting electric current from the work to be plated. The interior ofthe barrel cylinder is provided with a plurality of longitudinal ribs 36preferably of insulating material to efiect periodic tumbling ofarticles within the cylinder, as the cylinder rotates.

With electroplating barrels in which articles to be plated rest (withperiodic tumbling) in electrical contact with the inner metal surface ofthe plating barrel, it is a difficult matter (particularly with platingsolutions such as the chromic acid type of chromium plating solution) toobtain full coverage and uniformly appearing plate on work to beelectroplated. The difliculty of plating is also affected by the type ofwork to be electroplated, that is, by size, height, flatness etc. of thework. It has been found to be important in overcoming these platingdifficulties to avoid diversion of the current between the anode and thework on the inner surface of the plating cylinder, and also to providefor adjustment of the spacing between the anode and the inner surface ofthe plating cylinder, i. e., between the anode and work in contact withthe inner surface of the plating cylinder, as described later on.

For preventing diversion of plating current from the Work it has beenfound to be important 2' to insulate all parts of the plating cylinderexcept its inner cylindrical surface. In addition to the insulation 33,34 on the flanges 30, the outer surface of the metal cylinder I2 isinsulated, as indicated at 35, Fig. 2a.

The barrel cylinder is rotatably supported at one end only, above thelevel of the plating solution in the tank, as shown, so that only aportion of the circumference of the barrel cylinder is submerged as itrotates. the barrel cylinder is ashaft 40 attached to the cylinder atits axis, by any suitable means, as a spider 42 and a hub 44 having asplit, tapered, threaded end 45. The end of shaft 49 projects into thehub 44 and is clamped inside the hub by means of a nut 41 which nutforces the split end of the hub into binding electrical contact with theshaft as it is screwed on to the threaded, tapered end of the hub. Theshaft 40 is supported in bearings 50, which may be fastened on to aframe 52 attached to the tank It]. As the tank and frame are usually ofmetal, the bearings 59, 5] are insulated from the frame, as indicated at53, Fig. 7, to the end that the barrel cylinder I2 and shaft 40 areinsulated from other parts of the mechanism. The shaft 40 and barrelcylinder 12 mounted thereon is rotated at a suitable speed by a suitablemechanism, such as an electric motor reduction-gear unit 55, having anoutput shaft 56. Mounted on the shaft 56 is a pulley 57 and this drivesa pulley 58 fastened on the shaft 40 through a non-conducting chain orbeltfis.

Means are provided for connecting the barrel cylinder in an electriccircuit as a cathode, and these means are arranged remote from thesolution in the tank and fumes or spray arising therefrom, so as tothereby protect the electric contacts from fouling and causingresistance to the flow of the current. To this end, the remote end ofthe shaft 40 may be provided with an electrical conducting disk, which,as shown, may be integral with pulley 58. Brushes 6|, 62 are provided,and these bear on opposite sides of the pulley 58 so as to have slidingcontact therewith. The brushes are carried by a brush holder 64 attachedto an insulated bracket-65 carried by the frame 52, and the brush holder64 is connected with the oathode bus bar 61.

Numeral designates the anode, and this is carried by a shaft 12 whichprojects through the open end 28 of the barrel cylinder opposite end 29at which the barrel cylinder is supported, into the interio of thecylinder. The anode is removably attached to the shaft as by means ofscrews or bolts 13 to permit the substitution of The rotatable supportfor 7 anodes of different shape and diametrical pro jection for bestperformance with different types of articles to be electroplated. Theshaft 12, carrying the anode, is supported by means which function topermit the anode to be removed from the plating solution by a rotationof shaft 72, and which also permits the read removal of the shaft and.anode from the barrel cylinder and tank. To this end, the shaft 12 has acantilever support in a crotch type bearing 15 which opens upwardly, anda hook type bearing 71 which opens downwardly. The crotch type bearing75 may be, as shown, supported on the upper side of the tank, and thehook type bearing 'i'i may be arranged on an arm 19 attached to andprojecting outwardly from the side of tank It. The anode is electricallycomiected in a circuit by suitable means, as a flexible conductorelectrically connected to the shaft 72. The shaft 12 is insulated fromthe tank by suitable insulation as indicated at 82, 83. The height ofthe anode bearings i5 and 11 is adjustable. A suitable construction isillustrated in Fig. 12. As there shown, a bolt a passes through a holein the side of the tank and through a slot or series of holes in abracket 15b which carries the bearing 75, and by loosening andtightening the bolt 15a, or nut thereon, the height of the bearing f5may be adjusted and fastened in adjusted position to thereby obtain anoptimum spacing of the anode it from the Work on the inside of barrelcylinder E2. Likewise, a bolt 17a passes through a hole in bracket 79and through a slot or series of holes in a part 111) of bearing 71. Byloosening and tightening the bolt 11a, or a nut thereon, the height ofbearing T! may be adjusted and fastened in adjusted position. (alongwith the adjusted position of bearing 75) to obtain the aforesaidoptimum spacing of the anode 10 from the work resting on cylinder I 2.Work like thin washers require a different spacing of the anode from thebottom of the cylinder from the spacing for studs, for example, for goodevenly appearing, fully covering plating. For work of different sizesand shapes adjustment of the anode spacing is also necessary for goodplating results.

Work may be introduced and removed from the cylinder by hand or troughvia the open end of the electroplating barrel cylinder l2. Foradvantageously removing, or removing and supplying articles, from theinterior of the electroplating barrel cylinder I2, a demountable trough85, as illustrated in Fig. 5, or a double trough 81, as illustrated inFig. 6, may be provided. The trough extends from side to side across theinterior of the cylinder 12 and bears closely against the interiorsurface of the cylinder and has an open side 99 in the direction of therotation of the cylinder. The trough or 87 is fastened against theinterior of the barrel cylinder by spring strips 93 which are fastenedtothe ends of the trough, projecting outwardly over the flanges 3.8, 3| ofthe cylinder, and then'upwardly over the exterior surface of thecylinder so as to bear with spring pressure against the exterior surfacethereof, and thereby hold the trough against the interior surface ofthe'barrel cylinder. The trough 85 or 8'! acts tov scoop or collectarticles from the interior of the barrel cylinder as it revolves throughthe lowe arc with the rotation of the cylinder. The double trough 8?,illustrated in Fig. 6, also has the function of depositing new work inthe barrel cylinder for electroplating. The trough 81 is open at itsside 95 opposite the side 99, and is provided with a middle partition91. Articles may be placed in the trough 81 at the side of the partition91 through the opening 95, and as the barrel cylinder rotates. carryingthe trough 81, articles will be collected in the trough through theopening 90, and, as the rotation of the barrel cylinder continues,articles will be deposited in the bottom of the barrel cylinder from thetrough through the opening 95.

A second embodiment of the invention having means for continuouslyfeeding articles into and from the barrel cylinder is illustrated inFigs. 8 to 11. In Figs. 8 to 11, the shaft 40 is hollow as indicated atI and is provided on the inside with a spiral rib I02 for conveyingarticles lengthwise through the interior of shaft 40 into the interiorof barrel cylinder I2. Articles to be plated may be fed to the conveyorformed by the spiral rib I02 on the interior of shaft 40 by a hopper I04which may be supported in suitable manner as by means of an arm I05attached to the frame 52. The barrel cylinder I2 is also provided on itsinterior with a spiral rib I01, in addition to the transverse ribs 33.The ribs 36 and I0'I may be of metal, when low, but are mostadvantageously formed of an electrical insulating material, so as toavoid diversion of current from the work resting on the cylinder I2.These strips are also, chemically inert to the plating solution.Vinylite meets with these requirements. The

spiral ribs I07 act to slide articles lengthwise of the barrel cylinderas they are being electroplated. When the plated articles reach the sideof the barrel cylinder opposite the supporting shaft it, they are pickedup by pockets I I0 fastened to the cylinder adjacent to the flange 30,and as the pockets rise in the course of the rotation of the cylinderthe articles collected therein rise with them, and, when the pocketsreach a position at the top of the cylinder, the collected articles aredumped therefrom, and an inclined tray H2 is provided to catch them. Thetray I I2 may be removably supported at the side of the tank It asindicated at H2. The tray H2 is supported at an incline, and projectedinwardly through the open side 28 of the barrel cylinder and outwardlyover the side of the tank I0. As here shown, a tank I I6 may be providedat the side of tank It, containing water for rinsing the platingsolution from the plated articles. The plated articles may be thenreadily collected from the tank H3.

A third embodiment of the invention, illustrating another means forcontinuously feeding articles into and from the barrel cylinder isillustrated in Figs. 13 and 14. The structure of the embodiment of Figs.13 and 14 is generally the same as that of Figs. 1 to 4. In this thirdembodiment the barrel cylinder I2 is provided with an inside spiral ribI (similar to the rib III'I, Fig. 8) constructed and arranged to feedarticles resting on the cylinder I2 from the shaft supported end 29toward the opposite end 28, as the barrel-cylinder I2 is turned by itsdriving mechanism. As in the structure of Fig. 8, when the platedarticles reach the side of the barrel cylinder opposite the supportingshaft 40 they are picked up by pockets I23 fastened to the cylinderadjacent to the flange 33, and, as the pockets rise in the course ofrotation of the cylinder, the articles collected therein rise with them.When the pockets reach a position at the top of the cylinder, thecollected articles are dumped therefrom, and an inclined tray I isprovided to catch them. The tray I30 is supported at an incline, andprojected inwardly over the side of tank I0. The plated articles slidefrom tray [39 6 into a tank II6, similar to the plated articles in Fig.8.

Articles to be plated are fed into the cylinder by an electricallynon-conducting or surface insulated chute I which projects through theopen end 28 of the cylinder, at one side of the anode I0, and extends atits lower end to a point near the shaft supported side 29 of the barrelcylinder. The chute I35 advantageously has the form of a tube, which maybe expanded at its outer end to provide a funnel I36, and which at itsinner end is bent to one side at an angle of approximately 90, asindicated at I31, so that it may face the cylindrical wall of thecylinder I2. By bending the end I31 as described, articles sliding downthe chute I35 are deflected on exit toward the cylindrical wall of thecylinder, and are thereby kept from passing out of the cylinder I2through the openings in the end 29. Articles may be fed into the end I36of chute I35 by hand. However, an automatic hopper feed of any wellknown construction will usually be employed to feed articles to beplated to the end I36 of the chute. An automatic hopper feed isdiagrammatically shown in Fig. 13 at I40.

Operation The barrel cylinder I2 is rotated at a suitable speed from themotor gearing unit through pulleys 51, 58 and belt 59. For chromiumplating the speed of rotation should be such so that the articles beingplated within the cylinder are intermittently tumbled. The longitudinalribs 36 prevent sliding of the articles on the inside of the cylinderand assist in tumbling.

Plating current from a generator passes to the anode from conductor andshaft 12. Current passes from the anode through the plating solution tothe work resting in electrical contact with the cylinder I2, and thenfrom the cylinder I2, hub 44, shaft 40, disk or pulley 58, brushes BI.62, and cathode bus-bar 61 back to the generator.

The temperature of the plating solution is re ulated by controlling theflow of a thermal medium through the coil I4.

The exhaust fan 22 operates to remove fumes and spray arising from thesurface of the plating solution in the tank I0. The bearings 50, 5| andthe brushes BI, 62, being remote from this exhaust, are therebyprotected from fouling by the fumes and spray which would causevariations in the plating current. The electrical connections of themotor 23, motor 55 and anode are likewise V protected.

When plating of the articles in the barrel cyl-- inder I2 has beencompleted, in the construction. illustrated in Figs. 1 to 6 inclusive,the workmen. insert either a trough or a trough 81 longitudinally acrossthe interior of the barrel cylinder. The spring strips 93 projectalongside the outside: of flange 30 and thetongues of the strips bear:

on the exterior of the cylinder, and press the! trough against theinterior of the barrel cylinder;, with the edge of the opening bearingclosely, against the cylinder. The position of the trough: at the timeof attachment is shown in full lines: in Figs. 5 and 6. As the barrelcylinder rotates, and the trough passes through the bottom-most;position of the cylinder, the plated articles in the cylinder arecollected, as illustrated in dotted. lines in Figs. 5 and 6, and thenlifted up to a. position above the level'of the solution in thetank. Theworkman then separates the trough from the barrel cylinder, withdraws itthrough. the open end 28 of the cylinder, and then empties the contentsof the trough. To deposit articles to be plated in the barrel cylinderat the same time that plated articles are collected from the cylinder,the double trough illustrated in Fig. 6 is used. Articles to be platedare put into the side of the trough which opens upwardly. As the barrelcylinder rotates, the trough is carried through the lower position ofthe cylinder, collecting plated articles through the opening 90, asheretofore described, and, shortly thereafter, as the trough rises, theunplated articles are deposited in the barrel cylinder through the openside 95 of the trough. See the dotted line posi tion, Fig. 6.

When no more articles are to be plated, the anode I is moved out of thesolution to prevent the formation of an insulating chromate filmthereon. This is readily done by rotating shaft 12 which carries theanode until the anode is moved from the position shown in Fig. 3 to theI position shown in Fig. 4.

The shape and diametrical projection of the anode into proximity withthe surface of the barrel is of importance in obtaining good platingresults with different types of work. To make use of an anode bettersuited than another anode to the type of work being electroplated, thefastening means I3 are loosened or removed, and the proper anodesubstituted and then fastened in place.

To effect complete removal of the anode from the barrel cylinder andtank, as for replacing anodes, or for other purposes, the detachment isreadily effected. The shaft I2- on its cantilever bearing I5 is presseddownwardly at its outer end and lifted upwardly at its inner end, andthen simply lifted out of the barrel cylinder and-away from the tank.The shaft in, its tilted position free from the hook bearing I'I andthe; crotch bearing I5 being open at the top, offers no ob.- structiontothe removal of the shaft I2 and-Hanode I0. W

Referring to-Figs. 8 to 11', the operation of' the plating barrel islike that described in references to Figs. 1 to 6 except that thefeeding of the articles into and out of the barrel cylinder: I2 isautomatic;

In the construction illustrated in the later figures, the articles to beplated are fed, from the hopper I04 into the hollow in shaft 40, and arethen moved forward into the barrel cylinder by the spiral rib I02.The-articles fall into the barrel cylinder at the end adjacent, theshaft. 40, and on reaching the bottom of the cylinder they arecontinuously fed lengthwise towardthe open end 28 by the spiral rib I01.While the articles arebeing plated, they are intermittently tumbled withthe assistance of the ribs 36 and at the same time fed lengthwise alongthe'barrel cylinder by the ribs I07. At-the side 28 ofthe cylinder [2,the plated articles arepicked up by thepockets H9 and then lifted up inthe course of the rotation of the cylinderto aposition wherethe-articles are dumped out ofthe pockets. This position is shown inFig.8; The plated articles dumped fromthe pockets IIOv are caught'by'theinclined plate I I2, .and slide down theplate'to a place of delivery,for example a, water tank H6,

in which plating solution iswvashed from theticle into and out of thecylinder I2 is automatic, similar to the operation in Figs. 8 to 11. InFig. 13, articles to be plated are fed into the end I38 of the chuteI35, either by hand, or from an automatic hopper feed. The articles fedto the chute I35 slide down the chute and are discharged inside of thecylinder I2 adjacent the shaft supported end 29. From the shaftsupported end 29 of the cylinder I2 the articles are continuously fedlengthwise towards the open end 28 by the spiral rib I29. They are alsointermittently tumbled as in the embodiment of Fig. 8. At the side 28 ofthe cylinder, the plated articles are picked up by the pockets I25,dumped onto the inclined plate I30 and discharged into a washing tank II8, similar to the operation in Fig. 8.

What is claimed is:

In an electroplating barrel for barrel plating articles with chromium orwith other metals diflicult to electroplate comprising a tank forholding a plating bath, a rotatable open-ended articlesupportingmetallic cylinder supported on the tank for partial immersion in thebath, a horizontal conducting shaft electrically and structurallyconnected at one end of the cylinder by means of which the cylinder isrotated, means for electrically connecting the shaft to the cylinder, ananode supported in the cylinder, means for rotating said cylinder shaftand the cylinder connected thereto, and means for connecting saidcylinder and the anode in an electric circuit through the plating bath,the improvement in which said cylinder is imperforate, said cylinderhaving a conducting inner cylindrical surface and having electricalinsulation covering the outer cylindrical surface thereof to avoiddiversion of current between the anode and articles supported in saidcylinder, said electrical connecting means between the cylinder and itssupporting shaft comprising a split tapered threaded hub attached to thecylinder for receiving the shaft, and a nut for said threaded hub actingto force the split end of the hub into binding engagement and firmelectrical contact with the shaft, said hub and nut also permitting thecylinder to be detached from the shaft, said means for rotating thecylinder and cylinder shaft comprising a conducting pulley on thecylinder shaft an'da non-conducting' driven belt'for driving saidpulley, and said means'for connecting the cylinder and anode in anelectrical circuit including contact'brushes in contactwith saidconducting pulley.

GEORGE DUBPERNELL.

STEPHEN MI MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 703,623 Taylor July 1, 1902901,280 Daniels Oct. 13, 1908 1,185,946 Schulte June 6, 1916 1,609,357Hulmer Dec. '7, 1926 1,789,443 Levin Jan. 20, 1931 1,835,643 Frost et a1Dec. 3, 1931 1,899,679 Fink Feb. 28, 1933 2,133,324 Hosdowich Oct. 18,1938 FOREIGN PATENTS Number Country Date 23,267 Great Britain of 1897

